The present invention relates to a drilling guide for use in various orthopedic surgical procedures of the type requiring the drilling, along a common axis, of two differentdiameter bores through a broken bone.
There are a number of orthopedic surgical procedures used in the repair of broken bones which require carefully controlled drilling, along a common axis, and at different times during the procedure, of two different-diameter bores which are required for the subsequent insertion of repair hardware. Among the procedures in which the invention finds particular utility are those known as open reduction internal fixation of a hip, osteotomy of the hip, osteotomy of the proximal tibia, and open reduction internal fixation of supra condylar fractures.
A preferred embodiment of the invention is described herein, for illustration purposes, in connection with open reduction internal fixation of the hip.
Conventional open reduction fixation of a hip fracture, such as a fracture at the base of the neck in the femoral head, involves the insertion of a surgical screw, and the attachment of a holding plate to the external surface of the bone. Preparation for the insertion of the screw requires, according to a procedure to be discussed herein, precision common-axis drilling of two bores having different diameters at a predetermined angle relative to the longitudinal axis of the bone. The procedure commences with the insertion (drilling in) of a slender guide pin at predetermined angle. The inserted guide pin projects from the lateral cortex of the femur, and continues through the femoral neck into the femoral head. The guide pin is then used to align coaxially a hollow-core reamer which forms a larger-diameter bore around the guide pin in preparation for the insertion of a surgical screw and plate. The reamer is then removed, and a hollow-core surgical screw is installed--guided by the guide pin. Thereafter, the guide pin is extracted, and a surgical fixation plate is attached which allows fracture compression, while maintaining alignment of the fracture during healing.
Guide pin and reamer alignment have been accomplished using a variety of methods and devices in the past. According to one method, the guide pin is inserted (drilled) using a "fixed-angle" drill guide which has a bore conforming to the outer diameter of the pin, and which, during the drilling process, is attached to the femur. Such a device provides angular alignment for the guide pin but is not usable thereafter for guiding a reamer.
Another procedure employs a drill guide having an adjustable-angle guide head. This kind of device, vis-a-vis drilling, works somewhat like a fixed-angle drill guide, with the main difference being that the guide head can be adjusted to permit drilling at different preselected angles, as dictated by the particular circumstance. However, problems have been encountered in the past where the angular position of the guide head slips during use.
A significant problem in the past has been that existing guides do not provide support for a reamer, which, accordingly, has been aligned solely by a guide pin. This situation frequently results in a bent guide pin, which does not provide proper guidance, and which, after bending, is caught inside the reamer, causing the guide pin to be directed through the hip joint into the pelvis, and then removed with the reamer leaving the fracture without support or landmarks.
A general object of the present invention, accordingly, is to provide a novel drill guide usable in orthopedic surgical procedures like those outlined above, specially designed to accomodate accurate, secure guidance for drills of two different diameters for coaxial drilling during such a procedure.
Another object is to provide such apparatus which is simple in construction, and easy, accurate, and "sure-footed" during use.
According to a preferred embodiment of the invention, the same features a generally planar, somewhat C-shaped main guide body, or element, formed from a suitable plastic material which, conveniently, and to obtain an "in-use" advantage described below, may also be a radio-translucent material. The main guide body is formed with a non-slip handle which the physician may grip securely to position and manipulate the device adjacent a broken bone. An edge of this body opposite the handle is configured with a support surface for fitting snugly adjacent the femur during an operation, with pins projecting from this surface to furnish a high-friction, non-slip footing.
A bore of a predetermined angle (relative to the support surface) extends through the body, with the diameter of this bore being sized to furnish a clearance fit with a reamer of the type mentioned above.
A second, generally cylindrical, guide element, including a cylindrical body portion which fits within the bore of the first, or main, guide element, contains a second bore extending axially through the element. This bore has a smaller diameter than the first-mentioned bore, and specifically is sized to provide a clearance fit with a slender guide pin of the kind discussed earlier.
During a surgical procedure, with the main guide element placed and held against a femur, and with the second guide element assembled with the first element, the smaller-diameter bore just mentioned is used to guide the drilling insertion of a guide pin. The second guide element is thereafter removed by withdrawal along the axis of the guide pin, and the larger-diameter bore in the main guide element is then used to guide drilling of the reamer. After use of the reamer, the same is also withdrawn axially from the guide pin--supported during withdrawal by the bore wall in the first guide element, in a manner minimizing the likelihoood of bending the guide pin.
The main guide element is now removed from the surgical field, in either one of two different ways, according to the specific construction of "escape structure" provided according to two different modifications of the invention disclosed herein. According to one modification, the guide bore in the main guide element forms part of a specially shaped escape aperture. This aperture permits withdrawal of the first guide element by a first rotational movement in the plane of the element, to clear the support surface from any adjacent muscle tissue with which it may have become caught, followed by a second translational motion withdrawing it along the length of the guide pin. In a second modification of the invention, a lateral escape passage aperture is formed in the body of the first guide element, along one side of the guide bore therein, which passage permits withdrawal of the element by a first rotational movement generally normal to the plane of the element, to clear a guide pin from the guide bore, followed by a second rotational movement generally in the plane of the element to clear it from any adjacent tissue.
Various other features and advantages which are attained by the invention will become more fully apparent as the description that now follows is read in conjunction with the accompanying drawings.